What is a levain? Levain vs. sourdough starter, explained

A levain is a small preferment built from a spoonful of your mother starter for one specific bake. You mix it at whatever flour, hydration, and ratio that recipe wants, let it ripen, then use all of it. The mother stays on its own feeding schedule, untouched.

What is a levain, exactly?

"Levain" is French for leaven, and in France the word often means the sourdough culture itself. English-language recipes narrowed it: a levain is the batch you build from the culture, sized for one dough and consumed entirely in it. The mother you keep alive; the levain you make and spend.

One jar otherwise juggles two jobs — staying healthy long-term, and delivering ripe leaven at the right hydration, on schedule.

Levain vs starter: why bakers bother

• Flour freedom. Keep the mother on white flour, build the levain on whole rye. Whole grain ferments faster but is a nuisance to feed daily.
• Hydration freedom. A firm build behaves differently from a slack one, and you get either without converting the mother.
• Timing. Pick a build ratio that ripens when you plan to mix, instead of bending the feeding ratio you use on the mother around your dough.
• Volume. A loaf may want 200g of leaven. Keeping a 200g mother burns flour daily; keep 20–30g and build up.

How to make a levain: the arithmetic of a build

Builds are written starter : flour : water by weight. So 20g starter + 100g flour + 100g water is a 1:5:5, yielding 220g.

The starter brings flour and water of its own. If your mother sits at 100% hydration, that 20g is 10g flour and 10g water, so the levain totals 110g flour and 110g water — still 100%. Use 50g of water instead and you get 110g flour to 60g water, about 55% hydration. The baker's percentage math is the same as on dough.

Build 10–20% more than the formula asks for, because nobody scrapes a jar clean.

Ratio and temperature set the ripeness window

More flour per gram of starter means more food and a longer climb to peak. Near 76–78°F (24–26°C), rough windows run:

• 1:1:1 — about 4–6 hours
• 1:2:2 — about 6–8 hours
• 1:5:5 — about 8–12 hours
• 1:10:10 — long enough to run overnight

Treat those as starting points. Temperature swings them hardest — a 68°F kitchen can stretch the same build close to twice as long, which is how an overnight levain works without a proofer.

Read the levain, not the clock. A slack build is ripe once it has domed, roughly tripled, and webbed with bubbles through the side of the jar. A flat or dipped top means past peak: weaker lift, sharper acid, still usable.

Sourdough Tracker, a sourdough baking companion app for iPhone, keeps a levain build on its own timer, separate from the mother's feeding schedule.

Stiff levain vs liquid levain

A firm build — usually 50–60% hydration — behaves like a small piece of dough. It rises less than a slack one, domes and cracks instead of foaming, and takes longer to peak at the same ratio and temperature. It also holds near peak longer, forgiving a slipping schedule.

Flavor tends to move with it. Firmer, cooler, less frequently refreshed conditions push the acid balance toward acetic acid, the sharp vinegary note; wetter and warmer conditions favor lactic acid, which reads milder. That's a tendency, not a switch, and one of several levers on how sour the finished loaf tastes.

Tear a firm levain into the recipe's water and let it soften before mixing, or you'll chase lumps.

Sourdough terms compared: levain, starter, discard, poolish, biga

Term	What it is	Typical hydration	Leavened by	Fate
Mother starter	The culture you keep and feed indefinitely	50–125%, your choice	Wild yeast and lactic acid bacteria	A piece always stays back
Levain	An offshoot built from the mother for one bake	Whatever the formula wants	The same wild culture	Used up in the dough
Discard	Starter removed before a refresh	Same as the mother	Same culture, past peak	Pancakes, crackers, or the bin
Poolish	A loose preferment, equal flour and water	About 100%	A pinch of commercial yeast	Used up in the dough
Biga	A stiff Italian preferment	About 45–60%	A pinch of commercial yeast	Used up in the dough

The poolish vs biga difference is mostly hydration. Poolish, the French baguette preferment, is slack and lends extensibility and a nutty aroma. Biga, Italian and fermented cool, is stiff and lends strength with a milder note. Both classically run 12–18 hours on a small dose of commercial yeast — a sourdough biga is functionally a firm levain.

FAQ

Is a levain the same as a sourdough starter?

Not quite. A starter, or mother, is a culture you keep alive indefinitely; a levain is a portion of it built up for one bake and used entirely. Everyday French usage treats them as one word, which is where the confusion starts.

Can I use starter straight from the jar instead?

Yes, plenty of bakers do. If the mother is at the formula's hydration and ripe when you want to mix, adding it directly works — you just can't change flour or hydration for that bake.

How much levain does one loaf need?

Most formulas set the levain's flour at roughly 10–25% of the total flour — for a 1kg-flour recipe, that's about 200–500g of a 100% hydration build. Lower percentages ferment slower and suit warm kitchens.

What if my levain collapses before I'm ready to mix?

It will still raise bread, with less power and more acidity. Use it promptly and expect a longer bulk, or feed it again and wait for the next peak. Next time, lower the ratio or work cooler.

Does a stiff levain make bread more sour?

It nudges the balance that way rather than guaranteeing it. Low hydration favors acetic acid, and so do cooler temperatures and longer gaps between refreshes. Bulk length, cold retard, and flour choice pull just as hard.